1. Field of the Invention
This invention relates to an inhalation device.
2. Related Art
A propellant-free inhalation device with a supply of pulverized medical substance in a supply chamber, a manually actuatable metered dosing means in form of a rotatable dosing means having one or more peripheral recesses (dosing chambers) to receive in one position from the supply chamber the dose of the medical substance to be inhaled and to discharge the dose in another position, with a mouthpiece, formed at the side of the housing of the inhalation device for active inhalation and with an air channel for distributing the discharged dose in the breathing air flow and with at least one air intake embodied within the housing is described in DE 35 35 561.
In the known inhalation device the mouthpiece is arranged in such away that its axis extends parallel to the axis of the dosing means. Its air channel is guided underneath the dosing means to the opposite side of the housing where the air intakes are situated, by forming a cavity on the level of the dosing chamber. If due to a rotation of the dosing means the loaded recess (dosing chamber) is facing the air channel of the mouthpiece, the dose of powder that has been before discharged from the supply chamber falls, due to the gravity forces and--if desired--supported by a vibrating mechanism from the dosing chamber into the cavity of the air channel and is therefrom inhaled into the lungs of the patient by means of active inhalation. The air channel has a throttle area which is destined to promote the mixing of air with the medical substance by means of turbulence.
The known inhalation device has two critical drawbacks. On one hand the accuracy in dosing the powder to be inhaled and in emptying the dosing chambers is not satisfactory, on the other hand a reliable dispersion of the powder in the breathing air is not warranted. For proper handling of the known device both hands are necessary. Emptying of the dosing chamber and getting all the powder out of the mouthpiece is not guaranteed.